Corn plants are typically planted in rows spaced a predetermined distance apart. It is desired for the row spacing to be substantially uniform, but sometimes, for a variety of reasons, the distance between plants of adjacent rows can vary, sometimes by several inches. In has also become a practice to stagger the plants in the respective rows, e.g., in a zig-zag pattern, for instance, by planting alternating ones of the plants of the row on opposite sides of a centerline of the row, e.g., 3 or more inches from the centerline, such that the adjacent plants are 6 or more inches apart, for instance, to enable placing the plants closer together longitudinally along the row, or for more advantageously arranging nutrient zones for the plants. Still further, there are presently a variety of different row spacing standards, e.g., 38 inch, 36 inch and 30 inch (the latter the most popular in North America); and 80 cm, 75 cm, and 70 cm (the latter the most popular in Europe and the rest of the world). Narrower, e.g., 22 inch and 15 inch (55 cm and 40 cm), spacings are also contemplated.
Modern corn harvesting machines, particularly combines, but also defined here to include silage harvesters, choppers, and the like, have headers including harvesting or picking apparatus or units adapted for harvesting multiple rows of corn simultaneously. When configured as individual harvesting units such as those for harvesting only the corn ears, the units are typically spaced apart distances corresponding to the row spacing of the corn crop being harvested. These harvesting units are configured and operable for receiving the corn stalks and removing the full ears of corn, for conveying by other apparatus to processing apparatus within the harvesting machine. The typical harvesting unit includes a frame supporting forwardly extending, spaced apart dividers defining stalk receiving areas therebetween. The machine is driven such that the dividers are moved forwardly along and between the rows of plants such that the plants enter and pass rearwardly through the stalk receiving areas. The harvesting units include stalk handling apparatus at the rear of and in connection with the stalk receiving area, including stalk handling elements defining a processing or picking channel or gap therebetween into which the stalks are received. The stalk handling elements can comprise a variety of devices or apparatus operable for harvesting the corn ears from the stalks, including fore to aft moving gathering chains having teeth operable for carrying the corn ears rearwardly to the conveying apparatus of the head. The elements can also include fore and aft extending picking or snapping rolls located below stripper bars or plates bounding the channel or gap, the snapping rolls being rotatable for pulling the corn stalk downwardly to bring the stripper bars to bear against the ears to snap or separate them from the stalks. The cobs are then conveyed into the harvesting machine, while the collapsed stalks are left on the field.
Shortcomings observed with the known picking apparatus include a lack of non-row sensitivity, that is, an ability to smoothly intake corn plants spaced or offset from the center line of the picking gap or processing channel of the harvesting or picking units. For example, harvesting units spaced 70 cm apart will have difficulty smoothly harvesting corn plants in rows spaced 80 cm apart, etc. Problems observed include that the row dividers can become entangled with and run over or break off the stalks, or bend the stalks over, resulting in premature detachment and loss of corn ears. Avoiding these problems typically requires slowing the forward speed of the machine and a resultant reduction in productivity. The known apparatus have also been observed to have shortcomings for harvesting downed corn plants, e.g., having stalks bent or broken so as to extend at a small acute angle to horizontal, or even be located on the ground, as opposed to standing generally straight up.
Various additional apparatus have been proposed for enhancing feeding and processing of corn stalks, mostly within the stalk processing channel or picking gap of corn harvesting or picking units. Reference in this regard, Rauch U.S. Pat. No. 6,119,443 issued Sep. 19, 2000. While the Rauch device appears to provide advantageous row non-sensitivity, it is relatively large, involves multiple relatively rotating discs for chopping and/or conveying stalks from more than one stalk receiving channels into a picking gap, and has no ready ability for adaptation for use with a single harvesting or picking unit. There is also no observed enhanced ability to handle downed stalks, and if the discs contact the ground there is an increased risk of them picking up rocks and other debris which can then be conveyed into the harvester.
Reference also variously, Wolters et al., U.S. Patent Publication No. 20010003237 published Jun. 14, 2002; Wubbels et al., U.S. Pat. No. 6,487,839 issued Dec. 3, 2001; Wolters et al., U.S. Pat. No. 7,047,717 issued May 23, 2006; Wubbels et al., U.S. Pat. No. 7,395,649 issued Jul. 8, 2008; and Kapplehoff, U.S. Pat. No. 7,415,817 issued Aug. 26, 2008, each of which utilizes a tine wheel or wheels located mostly or completely above picking apparatus for assisting stalk flow and processing. Shortcomings observed of the above referenced devices for use with harvesting or picking units, include the location of the tine wheels too far above the picking apparatus and/or too far rearward to provide significantly enhanced non-row sensitivity, and so as to be largely ineffectual for aiding in the gathering of downed stalks.
Thus, what is sought is a harvesting unit for a corn header of an agricultural harvesting machine, having improved non-row sensitivity, with an enhance capability for use in downed corn, and which overcomes one or more of the shortcomings set forth above.